It was a "cozy night" earlier this month at the couple's Nottingham Cottage, at Kensington Palace, and the pair were roasting a chicken, the American actor said. Or trying to roast a chicken, Harry said, correcting her.

"It was so sweet and natural and very romantic. He got down on one knee," she said. "As a matter of fact, I could barely let you finish proposing. I said, 'Can I say yes now?'"

The pair laughed as they fondly remembered the moment. Harry continued, "There was hugs and I had the ring in my finger. I was like, 'Can I give you the ring?' She goes, 'Oh, yes! The ring!'"

"It was a really nice moment," the prince said. "It was just the two of us, and I think I managed to catch her by surprise as well."

These were among the revelations -- along with Harry's belief that Markle and his mother, the late Princess Diana, would be "thick as thieves" -- divulged by the royal couple-to-be in an interview with BBC's Mishal Husain that aired Monday evening, hours after they announced that they planned to wed following an 18-month romance.

How they met

Markle said she didn't think of theirs as a "whirlwind" relationship. The two met for a drink in July 2016 on a blind date, brokered by a mutual friend, whose name they would not reveal, but "it was definitely a setup," Markle said.

They didn't know much about each other. Markle wasn't too familiar with the British royal family, and Prince Harry had never seen the television show, "Suits," or any other example of Markle's work.

Harry recalled his first impression: "I was beautifully surprised when I walked into that room and saw her. There she was sitting there."

He thought, "I'm going to have to up my game."

Shortly after their encounter, they decided another date was in order.

"What are we doing tomorrow? We should meet again," Markle recalled asking.

Prince Harry was about to head off to Africa, and Markle was busy with work.

"We need to get the diaries out and find out how we're going to make this work," Harry thought at the time.

They had another date that month and then Harry was able to convince Markle to join him in Botswana a few weeks later. They camped out under the stars for five days, he said.

"Then we were really by ourselves, which was crucial to me, to make sure that we had a chance to get to know each other," he said.

Added Markle: "We were able to really have so much time just to connect, and we never went longer than two weeks without seeing each other even though we were obviously doing a long distance relationship. We made it work."

Diana 'a part of this with us'

That time in Botswana is represented on Markle's finger, as the primary stone on her engagement ring was sourced from the African nation. The smaller diamonds on the side of the ring came from his mother's jewelry collection.

He wanted to include those on the ring, which he designed himself, "to make sure she's with us on this crazy journey together."

Markle said she's glad she didn't know much about the royals before meeting Harry, as she's been able to learn about them from Harry himself rather than the tabloids.

"I think everything about Harry's thoughtfulness and the inclusion of that and obviously not being able to meet his mom it's so important to me to know that she's a part of this with us," she said.

Looking down at her ring, she said, "It's incredibly special to be able to have this, which sort of links where you come from and Botswana, which is important to us. It's perfect."

Asked if Markle and his mum would get along, Harry said, "They'd be thick as thieves, without question. I think she would be over the moon jumping up and down, so excited for me."

"It is days like today when I really miss having her around and miss being able to share the happy news, but you know with the ring and with everything else that's going on I'm sure she's with us, jumping up and down somewhere else."

It was a "cozy night" earlier this month at the couple's Nottingham Cottage, at Kensington Palace, and the pair were roasting a chicken, the American actor said. Or trying to roast a chicken, Harry said, correcting her.